This research proposal deals with chronic and acute effects of ethanol on gastric mucus and gastric mucosa. Since a definite evidence was obtained that ethanol depletes gastric epithelium of its extra- and intracellular stores of glycoproteins and glyceroglucolipids, and produces gastric mucosal injury resulting in the erosions, superficial ulcers and bleeding, these studies are aimed toward elucidation of chronic and acute effects of ethanol on biosynthesis of mucus glycoproteins and glyceroglucolipids. The qualitative and quantitative studies (in vivo and in vitro) will be performed on initiation of biosynthesis of the carbohydrate chains of glycoproteins and glyceroglucolipids and on their glycosylation. The effect of ethanol on sulfation processes of glycoproteins and glyceroglucolipids will be also studied, since the sulfated compounds are postulated to be involved in the protection of gastric mucosa. The in vitro biosynthesis systems, described in the proposal, are designed to discriminate between the effects of ethanol administration on the individual glycosyltransferases, on protein acceptors, and on lipid core acceptors. The measurement of the rate of incorporation of (14C)-N-acetylhexosamines, (14C)-glucose, (14C)-glycerol, and 35S, isolation and quantitation of label led and reduced oligosaccharides derived from glycoproteins, and of # glyceroglucolipids, will permit to determine whether ethanol affects the rate of glycosylation, qualitative composition, and the amount of the synthetized oligosaccharides of neutral and sulfated glycoproteins and of glyceroglucolipids. Studies in vitro with various chemically and enzymatically modified acceptors, and enzymes, both obtained from controls and ethanol treated rats, will be performed in combinations which will allow to follow the effect of ethanol on one variable at the time. These studies will allow to conclude whether ethanol produces lasting changes in the sturcture of the carbohydrate portions of glycoproteins and of glyceroglucolipids, or whether its action is exerted on the preformed mucus only, and leads to the disconcerted process of removal and formation of the protective mucous lining.